High-tension circuit-breakers generally comprise at least two superposed insulating columns which are bolted together, with one of the columns delimiting a circuit-breaking chamber and with the other containing an operating rod. These columns are filled with a dielectric gas under pressure, e.g. sulfur hexafluoride (SF.sub.6).
Circuit-breakers of the above-specified type require a gas-regenerating element, since each time the circuit-breaker interrupts a current, the dielectric qualities of the gas deteriorate and this can lead to a dangerous loss of circuit-breaker performance capacity.
French patent application No. 79 29498 filed Nov. 30, 1979 (corresponding to U.S. Pat. No. 4 386 250) describes a circuit-breaker having components which can be assembled and disassembled with little loss of dielectric gas. However, this circuit-breaker does not provide for the inclusion of a regenerator element.
Circuit-breakers are also known which include a regenerator element (a molecular sieve). One such circuit-breaker is shown in accompanying FIG. 1 which is fragmentary diagrammatic axial section through one pole of a puffer SF.sub.6 gas circuit-breaker. The pole comprises a circuit-breaking chamber 2 closed at its ends by a plate 2A and by casing 5, together with an insulating support 3 which is closed at its ends by end plates 3A and 6. A molecular sieve 4 is disposed between the casing 5 of the circuit-breaking chamber 2 and the top end plate 6 of the support 3. SF.sub.6 gas exchange takes place between the chamber 2 and the support 3 through the molecular sieve 4 via a passage 7 through the casing 5 of the chamber 2, and via a passage 8 through the top end plate 6 of the support 3.
The circuit-breaker is operated by means of an actuator 9 fed from a source of energy that enables a piston 10 to be displaced alternately upwardly and downwardly, said piston 10 being connected to an arc-blasting device 11 in the chamber 2 via an insulating rod 12 and a rod 13 forming a part of the moving contact 21, which rods are connected together by a device 14. The fixed contact is referenced 22. The two enclosures of the chamber 2 and the support 3 are sealed by means of sealing rings 15, 16, 17, 18, 19, and 20. In this type of circuit-breaker, it is impossible to assemble or disassemble the components or to replace the molecular sieve 4 without losing SF.sub.6 gas and without ingress of air.
In most cases circuit-breakers operate at fairly low voltages and are relatively compact, thereby enabling an entire circuit-breaker to be packaged without difficulty for transportation purposes.
However, very high tension circuit-breakers are very bulky and present packaging problems for transportation purposes. As a result, it is advantageous to be able to deliver such equipment in separate component parts which are factory-processed and inflated at low pressure, which can then be assembled on site without ingress of air into pressurized gas enclosures therein, and which can finally be raised to operating pressure without further steps, e.g. of gas purification. It is also advantageous to be able to insert the molecular sieve at the last moment on site, i.e. just before the circuit-breaking chamber is assembled onto its insulating support.
It is even more advantageous to be able to disassemble a circuit-breaking chamber from its support without spoiling the sealing of either enclosure, and then to be able to replace the molecular sieve, where necessary, while maintaining both enclosures properly sealed.
A circuit-breaker in accordance with the present invention satisfies these criteria.